1. Technical Field
The present invention relates to a battery pack and, more particularly, to a spacer placed between battery cells when making a battery pack.
2. Related Art
Unlike the primary battery, the secondary battery may be recharged, and may be made into a battery pack and used as the power source for various portable electronic devices such as cellular phones, laptop computers, and camcorders.
In particular, the lithium secondary battery among the secondary batteries is more suitable for portable electronic devices since it has a high driving voltage and a high energy density per unit weight. The lithium polymer battery is a type of lithium battery which uses polymer electrolytes, and has the advantage of making portable electronic devices slim and lightweight because it is flexible so as to form various shapes, and its weight is light.
Generally, the battery pack includes battery cells which are prepared separately, a case receiving the battery cells, and a spacer placed between the battery cells when a plurality of the battery cells are placed inside the case.
The spacer is placed between the battery cells to prevent electrical contact between the battery cells, and the spacer supports both sides of the battery cell when the battery cells are placed inside the case so that it plays a role in making the battery cells tightly fixed.
The spacer which has been suggested or used for the battery pack up to the present is devised so as to have a contact area with the battery cell which is as large as possible. This enables the spacer to support the battery cells by area contact so that more supporting power is added to the battery cells so as to fix the battery cells more tightly.
Accordingly, by way of example, when the battery cell has a cylindrical shape, the spacer has a curved surface corresponding to the circumferential surface of the battery cells so as to contact the outer surface of the cylindrical battery cell. One example of such a technology is described in Japanese Patent Laid-Open No. 5-290821.
However, such battery packs have a problem in that the life of the battery cell is decreased due to the fact that heat generated by the battery cells disposed inside the case cannot easily flow out of the case. That is, since the conventional battery pack, as described above, has a structure such that the spacer disposed inside the case is in close contact with the battery cells, it has an advantage in terms of support of the battery cells. However, since there is no passage through which the heat generated by the battery cells can flow out of the case, the heat remains inside the case and has a harmful effect on the battery cells.
Accordingly, the consumer who uses an electronic device having the secondary battery as the power source suffers inconvenience in using the electronic device because it cannot be sufficiently supported by the power source of the secondary battery.